The examination of samples, such as by metallographic examination, requires a number of preparatory steps. For example, a sample may need to be cut or sectioned to a specific size prior to mounting for examination.
Saws are known for carrying out the sectioning, e.g., cutting of samples. One such saw is disclosed in Weingart, U.S. Publication 2012-0100780, the disclosure of which is incorporated herein by reference in its entirety.
In a typical sample preparation saw, the blade is sacrificial. That is, the saw blade loses mass (and size) as cutting progresses. Blade size is lost in that the diameter of the blade is reduced as cutting is carried out.
In operation, the blade moves from a non-contact, home position vertically, along an arc, to contact the sample being cut. During the cutting operation, the blade typically moves along the arc slowly so as to properly effect the cut. Movement of the blade along the arc from the home position to the sample is also carried out at a relatively slow rate in that it is difficult to determine when the blade will contact the sample. As such, in an automated cutting operation time and efficiency (e.g., the number of samples cut in a given period of time) can be lost.
Additionally, many such saws have blades that translate laterally, parallel to the blade axis, to carry out a number of cuts in succession in the sample. During such operations, the blade returns to the home position following or between each cut. Again, because of the slow movement of the blade during the non-contact portions of cycle, it is inefficient to return the blade to the home position after each cut and prior to translation.
Accordingly, there is a need for an improved system for monitoring the position of the blade relative to a sample in a sample preparation saw. Desirably, such a system detects blade size and blade contact to vary the speed and distance that the blade travels during and between cuts of the sample.